1,2 Nuni Gofar, 1,3Hary Widjayanti, and 1,4NI Luh Putu Sri Ratmini
1Researcher at Research Center for Sub-optimal Lands, Sriwijaya University. Jl. Padang Selasa Palembang-South Sumatra. Phone / fax:0711352879; Email: firstname.lastname@example.org 9Corresponding author email: email@example.com)
2Department of Soil Science, Faculty of Agriculture, Sriwijaya University. Palembang-South Sumatra
3Departement of Biology, Faculty of MIPA, Sriwijaya University. Palembang-South Sumatra
4South Sumatra Assesment Institute for Agricultural Technology. Jl. Kol H. Barlian No.83 Km.6. Palembang-South Sumatra. Email: firstname.lastname@example.org
Abstract. This research was done to obtain phosphate solubilizing bacteria (PSB) indigenous from fresh-water Inceptisols that were highly capable of dissolving soil p. The research consisted of two sub-experiments. Sub-experiment I was to isolate the indigenous PSB from rhizosphere of rice, corn, and beans that were grown on fresh-water Inceptisols. Sub-experiment II was to study the ability of isolated PSB to dissolving soil saturated with AIPO4 with a dossages of 0, 10, and 20 g of AIPO4. Isolation and count of the bacterial population obtained were PSB population of 3.06-50.27X106 cfu g-1 soil and 5 isolates able to form clear zones on the Pikovskaya’s medium. In soil saturated with 10 and 20 g AIPO4 kg-1,, the best isolate increasing the P availability was I1. The total P increases were significantl correlated with the increases of available P. P concentration in the soil as an indication of phosphate solubilization capacity. The increases of soil pH value were significantly correlated with the increases of soluble P. In the acid soils, PSB BLOCKED P sorption by binding elements and reducing the toxicity of AL3+ and Fe3+ on plants.
Keywords: Fresh water, Inceptisols, PSB, Soluble P
Phosphorus (P) element is a major growth-limiting nutrient and referred as master key element in crop production (Saxena and Sharma 2003). Unlike the case for nitrogen, there is no large atmospheric source that can be made biologically available (Ezawa et al. 2002). The soluble forms of phosphorus, when applied to soil as phosphate fertilizers, are rendered insoluble by undergoing chemical fixation. However, more than 80% of the added P becomes immobile in acid soils and unavailable for plant uptake because of the strong fixation into unavailable complexes (Hilda and Fraga 2000).